244 EARTHQUAKE WAVES. 



detached areas of high temperature were moving eastward. On the after- 

 noon of the 15th the isotherm of seventy curved into Canada and across 

 the lake into Dakota, giving Northern Minnesota a higher temperature than 

 JSfew Orleans. Thus the heat erea became more clearly outlined and now 

 covered the United States from the northern frontier to the Gulf. On the 

 16th the isoutherm of 70 moved southward in the Northeastern districts, 

 but still maintained its position in the Northwest. The heat decreased in 

 Nova Scotia, the St. Lawrence Yalley and Northern New England, but in- 

 creased decidedl}^ in the Middle States, the afternoon record at New York 

 being 79 degrees. In Missouri a considerable variation of temperature 

 took place, and a violent tornado resulted between Fulton and Alton. The 

 heat in Wisconsin rose to 86 degrees, when it was only 71 at Cincinnati. 

 On the 17tli still more extraordinary variations occurred in the west, far 

 northerly points being extremely warm, while more southerly places had 

 comparatively cool weather. The temperature at New York fell to 76 and 

 at Boston to 53 degrees. But yesterday it rose again here to the highest 

 yet recorded, namely, 83 degrees, and still higher at Philadelphia, Pittsburg 

 and Baltimore, being 92 degrees at the last named city. The great heat 

 area is, however, passing oil the continent; the temperature is falling rap- 

 idly in the North and Northwest, and though we now experience a midsum- 

 mer heat, we shall after a few days feel proportionately chilly when the cool 

 wave is jDassing over us. During the heated term here the temperature 

 varied onh^ slightly on the Pacific coast. — Neio York Herald. 



IiIarthquake Waves. — Assistant Davidson telegraphs C. Peterson, 

 'Superintendent of the Coast Survey, in relation to the earthquake waves 

 registered in the tide guage at Port Point, at the entrance of San Francisco 

 harbor. May 12, to the following effect: '^ Sharp earthquake weaves com- 

 menced Thursday, May 10, at 6:18 A. m. Five rises and falls of 9 inches in 

 eight}^ minutes; then nine maxima, or crests, forty-eight minutes apart, 

 with secondary maxima, the largest 15 inches ; then six sharp rises of l-l 

 inches each ; irregular, broken crests one hour apart ; then, to 5 A. M. Fri- 

 day, double maxima, as at the commencement; largest rise, 8 inches, from 

 5:20 A. M., Friday, to 1:15 v. M., irregular maxima ; then a sudden fall to 16 

 inches, and action continuing until 5 P. m. No w^ell defined maximum of 

 action by expeditions of markedly different characters. The earthquake 

 wave of the great earthquake in Japan some years ago was 23 minutes 

 traversino' the Pacific to San Francisco." 



